This problem is kinda annoying as B is in Tesla, q is a charge, m is a mass right? Well here's a nice little trick:

Do you know the Lorentz force law? F = q(E + v x B)? On one side is a force, something with units you should know and are far more comfortable with. On the other side, it has these crazy coulomb and tesla units! I'll assume you may not have gone over it but basically, dimensionally F = qvB! From there you should be able to figure it out.